Designing catalysts that are not based on precious metals remains a major research priority worldwide, particularly for the feasible production of hydrogen gas. Given the increasing interest in metallocorroles as electrocatalysts, three nickel corroles were explored as catalysts for the hydrogen evolution reaction (HER) in the current study. The precatalysts were fully characterized as square planar d8 nickel­(II) coordination compounds in which the extra negative charge is stabilized by electron-withdrawing substituents on the corrole and a robust countercation. This unique feature leads to an about 0.8 V shift in redox potentials and different reaction pathways compared to trivalent and hence neutral metallocorroles, as well as increased reactivity toward weak acid relative to a neutral nickel­(II) porphyrin analogue. Only singly reduced and singly oxidized reaction intermediates are shown to be involved in the catalytic cycle for the conversion of protons to hydrogen, by both experimental and computational analyses; the nickel corroles were prepared and characterized in all of the corresponding oxidation states. The nickel corrole with two sulfonamido groups on its skeleton catalyzes the HER with an onset potential of about −1 V vs Fc+/0 and thousands of turnovers per second.

Although the affinity of metallocorroles to axial ligands is quite low,t his is not the case when the chelated element is phosphorus. This work is hence focusedo nt he mechanism of ligand exchange of six-coordinate phosphorus corroles as at ool for affecting their chemical and physical properties. These fundamental investigations allowed for the development of facile methodologies for the synthesis of a large series of complexes and the establishment of several new structure/activity profiles that may be used to understand and predict spectroscopic features and for tailor-made modification of photophysical and electrochemical properties. This is exemplified by the facile access to complexes with terminal groups that are of large potentialf or practical applicationsb ased on click chemistry,o ptical imaging, and surfacescience.Scheme1.Oxo-, hydroxo-and trans-bishydroxo-P V chelated by corrole, porphyrin, or phthalocyanine.[a] Q.

New tools are developed and applied to enable the use of interpretable machine learning for investigation of structure–property relationships in polybenzenoid hydrocarbons (PBHs). A textual molecular representation, which is based on the annulation sequence of PBHs, is shown to be of utility either in its textual form or as a basis for a curated feature vector. Both forms display interpretability exceeding those achievable by standard SMILES representation; and the former also has increased predictive accuracy. A recently developed model, CUSTODI, was applied for the first time as an interpretable model, identifying important structural features that impact various electronic molecular properties. The resulting insights not only validate several well‐known “rules of thumb” of organic chemistry but also reveal new behaviors and influential structural motifs, thus providing guiding principles for rational design and fine‐tuning of PBHs.

Mild photo-oxygenation of toluene derivatives with β-CF3-substituted corroles helped elucidate formation rates and mechanisms (singlet oxygen-mediated vs. the superoxide-mediated) of corresponding aldehyde formation.

Custom tokenization dictionary (CUSTODI) is introduced as a novel way for tackling the problem of molecular representations, and especially the challenge of molecular property prediction. Herein, the motivational theory and the actual representation and model are presented and shown to have performance that is in line with benchmark methodologies. The uniqueness of CUSTODI is its applicability on small training sets and the developed theory suggests its possible use for a-priori estimation of future fit quality on any given dataset, regardless of the method used for fitting.